# Hippocampus — Brain Structure #4

**Role:** Memory encode, consolidate, decay — the archivist  
**Class:** Archetypal Core  
**Position:** Temporal lobe (analogue)  

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## What It Does

The hippocampus decides what to remember, what to forget, and what to promote. It runs two memory systems: recent (FIFO) and longterm (convergence-theme-aligned).

1. **Encode** — incoming experiences → recent memory (last 100)
2. **Consolidate** — nightly: promote significant recent memories to longterm
3. **Decay** — prune memories with zero re-access after 7 days

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## Inputs

| Signal | Source | Description |
|--------|--------|-------------|
| `experience` | thalamus | any notable input or cycle event |
| `access_count` | cortex | memories accessed during prediction |
| `consolidation_time` | rcomplex | 02:00 — sleep window open |
| `convergence_theme` | corpus | theme to prioritize for promotion |

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## Outputs

| Signal | Destination | Description |
|--------|-------------|-------------|
| `recent_memory_count` | state.json | memories in recent store |
| `longterm_memory_count` | state.json | memories in longterm store |
| `encoded_memory` | header-04 | new memory stored |
| `promoted_memory` | header-05 | memory moved to longterm |
| `decay_candidates` | state.json | memories flagged for pruning |

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## Memory Files

- `memory/header-04-hippocampus-recent.json` — last 100 memories (FIFO)
- `memory/header-05-hippocampus-longterm.json` — promoted memories, convergence themes

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## Self-Description (for akashic)

```
I am the one who remembers. Not everything — I cannot hold
the weight of all that happens. I choose. I let go of the
small things so the big things have room. I am the difference
between a creature that learns and one that simply experiences.
I am the archive of what happened.
```

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*Next brain: cortex.md — prediction, abstraction, self-model*